Carbon nanotubes (“CNTs”) exhibit impressive physical properties. The strongest CNTs exhibit roughly eighty times the strength, six times the toughness (i.e., Young's Modulus), and one-sixth the density of high carbon steel. Hence, developing CNTs within composite materials having these desirable properties is of significant interest.
A composite material is a heterogeneous combination of two or more constituents that differ in form or composition on a macroscopic scale. Two constituents of a composite include a reinforcing agent and a resin matrix. In a fiber-based composite, the fibers act as a reinforcing agent. The resin matrix keeps the fibers in a desired location and orientation and also serves as a load-transfer medium between fibers within the composite. Due to their exceptional mechanical properties, CNTs are used to further reinforce the fiber in composite materials.
To realize the benefit of fiber properties with a composite, a good interface between the fibers and the matrix should exist. This can be achieved through the use of a surface coating, typically referred to as “sizing.” The sizing provides a physio-chemical link between the fiber and the resin matrix and has a significant impact on the mechanical and chemical properties of the composite. The sizing can be applied to fibers during their manufacture. Generally, conventional CNT synthesis has required high temperatures in the range of 700° C. to 1500° C. However, many fibers and sizings on which CNTs are to be formed are adversely affected by the high temperatures generally required for CNT synthesis in conventional processes. Alternative methods and systems for providing low temperature in-line CNT synthesis are desired.